Electric-arc lamp



(No Model.)

B. E. THURSTON.

ELECTRIC ARC LAMP.

No. 476,700. Patented June 7, 1892.

A TTOHNE Y8,

U NITED STATES PATENT OFFICE.

ROBERT H. THURSTON, OF ITHAOA, NEXV YORK.

ELECTRIC-ARC LAM F.

SPECIFICATION forming part of Letters Patent No. 476,700, dated June '7,1892.

Application filed February 27, 1892. Serial No. 423,026. (No model.)

To all whom it may concern:

Be it known that 1, ROBERT H. THURSTON, of Ithaca, in the county ofTompkins and State of New York, have invented a new and usefulImprovement in Arc Lamps, of which the following is a specification,reference being had to the annexed drawings, forming a part thereof, inwhich- Figure 1 is a side elevation of an arc lamp to which myimprovement has been applied. Fig. 2 is a plan view of the carbons. Fig.3 is a side elevation of the carbons, and Fig. 4 is an enlarged sideelevation of the ends of the carbons.

In Figs. 2, 3, and 4 the angle made by the carbons with each other isexaggerated to clearly illustrate the positions of the carbons relativeto each other.

Similar letters of reference indicate corresponding parts in all theviews.

In the operation of the well-known form of electric lamp employing broadflat carbons much difliculty is experienced in Windy weather from theshaking of the carbons past one another and their jamming and weldingtogether in that position, thus extinguishing the lamp.

The object of my invention is to obviate this difficulty, thus renderingthe operation of the lamp reliable.

My invention consists in twisting one of the carbons so that its endwill form a small an gle with the other carbon, thus preventing theirpassing.

In carrying out my invention I employ a lamp of any well-knownconstruction,in which are used broad flat carbons, and I turn one of thecarbons (preferably the lower one) so that the end will form a slightangle with the carbon with which it contactsthat is to say, I arrangethe fixed carbon in a plane which forms a slight angle with the plane ofthe movable carbon, the said angle being only sufficient to prevent themovable carbon from passing the fixed one. In the drawings I have shownthis angle greatly exaggerated to better illustrate the principle of myinvention. The angle in practice is not so large as to make any materialdifference in the length of the are formed between the center and theends of the carbons.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- An electric lamp having broad fiat carbons moving inthe same vertical line or in approximately parallel lines, with thecarbons arranged in planes intersecting at a smallangle for the purposeof preventing the carbons slipping by each other when shaken by the windor other force, substantially as specified.

HARRIS J. RYAN, JOHN H. BARR.

